Add Hardhat support

[zomglings]

Hardhat build artifacts differ from Brownie build artifacts as follows:

1. Build artifacts are put into the artifacts/ directory instead of the build/ directory. artifacts/contracts/ contains the contract ABIs.
2. Brownie build/contracts/ has a flat structure. Hardhat artifacts/contracts/ reflects the directory structure of the contracts/ directory containing solidity files.
3. Hardhat contract JSON files have a contractName field that defines the name of the contract in question. They also have a sourceName question that contains the path to the source (solidity) file from the hardhat project root.

Inspector Facet should support getting ABI side-information from hardhat project directories in addition to brownie project directories.

TODO:

• [ ] Implement hardhat support.
• [ ] Open question: Should there be a flag on inspector-facet that the invoker uses to specify whether they want to get ABI information from a brownie project vs. a hardhat project? Or should it be auto-detected?
• [ ] README should be updated explaining how to use inspector-facet with Hardhat projects. One potential area of confusion is that inspector-facet uses brownie to pull smart contract information and so requires brownie networks setup correctly. This has no bearing on whether it gets side information from a brownie project vs. a hardhat project. We should clarify this in README.